1. Field of the Invention
This invention relates generally to rotary oil-type dampening devices and more particularly, it relates to an improved high torque damper device which can be easily adjusted so as to produce variable amounts of torque over a predetermined range.
2. Description of the prior art
A prior art search directed to the subject matter of this application in the U.S. Patent and Trademark Office revealed the following U.S. Pat. Nos.:
______________________________________ 4,426,752 4,638,528 4,527,675 4,694,530 4,618,039 4,938,322 ______________________________________
It is generally known in the art that an oil-type damper device can be incorporated as a mechanism for controlling the opening and closing of doors and drawers in order to absorb the shock imparted by an external force. Such oil-type damper devices find convenient application, for example, in automotive vehicles where the opening of a door of a glove compartment mounted in a dashboard is prevented from occurring with a snap action, thus avoiding the contents thereof from being scattered. Since the glove compartment may be filled with objects of relatively heavier weight as compared to those in an ashtray, such a damper device is normally required to be designed to have a high-torque strength against the external forces. As a result, this causes the disadvantage that these damper devices become very large in their overall size and are quite bulky.
Further, the doors of the glove compartments in the automotive vehicles are known to come in various sizes and weights. Accordingly, there is encountered another drawback if a damper device having a different dampening effect is required. This is because a completely new damper device would be needed so as to accommodate the various weights of the doors. Heretofore, these prior art damper devices were only capable of altering their dampening effect by varying the viscosity of the oil used. Therefore, this made the conventional damper devices generally unusable for different types of doors and involved the use of expensive manufacturing of alternate components and time-consuming labor costs.
In U.S. Pat. No. 4,527,675 to N. Omata et al. issued on Jul. 9, 1985, there is disclosed an oil type damper which includes a cylindrical housing formed of a base 1 and a cap 2, a rotator 10 having a hollow shaft 12 and a braking disk 11, and a flexible membrane 16 fitted around the shaft. A toothed wheel 13 has a pin 13a which is adapted to be forced into the hollow part of the shaft 12. The oil is injected through the hollow part of the hollow shaft after the rotator and the flexible membrane have been set inside of the housing but before the toothed wheel is secured to the hollow shaft. The flexible membrane is used to absorb thermal expansion of the oil and prevents leakage thereof along the hollow shaft and out of the housing.
In U.S. Pat. No. 4,638,528 to N. Omata issued on Jan. 27, 1987, there is disclosed an oil type damper which is somewhat similar to the '675 patent. In particular, the '528 patent teaches an oil damper which is comprised of a housing formed of a basic member 1 and a cap 2, a rotating member 10 having a disc 11 and two shafts 12, 13, and a braking disc 15 adapted to rotate jointly and accommodated within the housing. The first shaft 12 has an end protruding through the boss 7 in the cap 2 for receiving a toothed wheel 14. A flexible member 17 is secured to the second shaft 13, with the flexible member being disposed between the disc 11 and the disc 15. Viscous oil is applied to the braking disc. When the oil expands in volume due to rising temperatures, the flexible membrane 17 is deformed under pressure so as to absorb the voluminal expansion of the oil and thus prevents leakage of the oil from the housing.
U.S. Pat. No. 4,694,530 to P. Foggini issued on Sep. 22, 1987, discloses a device for controlling the opening and closing of moving objects, such as doors and drawers in motor vehicles. The device 15 is comprised of a rotor 18 and a stator 17. The rotor 18 has a central pin 183, a plurality of concentrically arranged cylinders 180-182, a sprocket wheel 14 adapted for meshed engagement with a rack 13 fixed to the sidewall of a drawer compartment 12. The stator 17 is adapted to be attached to a drawer 10 and is rotatably mounted on the central pin 183. The stator is further comprised of a plurality of concentrically arranged cylinders 170-172 interposed between those of the rotor. The relative movement between the rotor 18 and the stator 17 is controlled by an arrangement of co-operating grooves 20,21, a cam 22, and a ball 23, and a high density fluid LS is interposed between the cylinders of the rotor and stator for slowing down the relative rotary motion therebetween.
The remaining patents uncovered from the search but not specifically discussed are merely cited to generally show the state of the art and are directed to various types of dampening devices for braking and absorbing abrupt motions encountered during the opening and closing of movable objects such as doors, drawers, and the like.
It will be noted that none of the prior art uncovered in the search disclosed a high torque damper device like that of the present invention which can be easily adjusted so as to produce variable amounts of torque over a predetermined range. This is accomplished in the present invention by simply rotating the cap so as to increase or decrease the distance between a plurality of co-mating concentric rings formed on a rotor and a stator housing in order to vary the frictional load.